I agree the i7 isn't considered a "Gaming CPU" its considered a workstation high volume chip not a gaming chip...
Could you talk any more crap? Intel have, you know, workstation chipsets and CPU's? "x79" spring to mind? Anyway here's Intel's website:
http://www.intel.co.uk/content/www/uk/en/processors/core/core-i7-processor.html
As you can clearly see, they advertise the core i7 as a high performance "top-of-the-line" gaming processor.
Sure, the i5 does nearly as good a job, but not quite as good as the i7, this is usually mainly down to the extra L3 cache on tap, but we won't go into the technical details as its all on the Intel website.
You'll also notice that generally on the whole, in pretty much every review of the i7 vs the i5 across the internet the world over, i7 beats the i5 by a frame or two in all games, but that's exactly it, its only a frame or two, to some (such as yourself I should imagine) that's a waste of $100, for someone like me, who wants the extra frame or two, I'm happy to pay the extra.
But as we were originally talking about pure performance, the i7 is more powerful in almost every way over the i5.
If you would like to know what Intel workstation CPU's are and why they are different here's a few links from Techspots own review of them and Intel's website:
https://www.techspot.com/review/465-intel-sandy-bridge-e-core-i7-3960x/
http://www.intel.co.uk/content/www/uk/en/processors/core/core-i7ee-processor.html
Even the Workstation Processors on the first page I found mention gaming, seems as if people are prepared to pay another £500 for an even more powerful processor! Shock horror!